Field of the invention

[0001 ] The present invention generally finds application in the field of packaging and bagging plants and particularly relates to a machine for automatically filling and selling valve bags.

[0002] In a further aspect, the invention relates to a method of filling and sealing valve bags using the above discussed machine.

Background art

[0003] Bags having a filling mouth with a check valve have been long known to be used for packaging various bulk products, such as powdered or granular products, such as feeds, fertilizers, seeds, cement, plaster or other similar products.

[0004] Particularly, the valve has an adhesive layer therein, which is adapted to be melted by heating to assist sealing of the mouth once the bag has been filled.

[0005] Bags are preferably filled and sealed using machines equipped with appropriate filling means and at least one device adapted to emit electromagnetic waves in the radio-frequency range as well as ultrasounds for causing the adhesive layer proximate to the filling means to be heated.

[0006] One drawback of this prior art arrangement is that the particular arrangement and configuration of the filling means and the device for sealing the valve are not able to seal a bag at the same time as another bag is being filled.

[0007] This drawback will extend the overall processing times and considerably reduce the throughput of the machine in terms of hourly yield of filled bags, ready for distribution.

[0008] Furthermore, with these machines, once the bag has been filled, it must be overturned or partially tilted o expose the portion with the valve, which must be sealed by the sealing device.

[0009] US 4,688,370 discloses a machine for filling and sealing valve-bags as described above, which is adapted to contain granular material. [0010] The machine comprises a bag-filling station having a nozzle connected to a reservoir for delivering the granular material and a tilting base below the nozzle, for supporting the bag.

[0011] A bag-sealing station is also provided, which has a sealing head connected to a radio-frequency electromagnetic wave emitter for sealing the valve of each bag.

[0012] Each bag is transferred from the filling station to the sealing station by means of a moving arm, which is adapted to receive the bag in a lying position from the base that is tilted. Furthermore, the arm comprises a sliding portion, which is adapted to place the bag proximate to the sealing device and to unload it onto a sliding belt once the valve has been sealed.

[0013] A first drawback of this arrangement is that the moving arm is placed before the filling station and actually prevents positioning of a new bag to be filled while the first bag is being transferred at the sealing device.

[0014] A further drawback is that each bag is completely overturned by the tilting base on the moving arm as it is being transferred from the filling station to the sealing device.

[0015] This drawback may cause loss or spillage of granular material from the interior of the bag to the outside, or possibly damages to the paper of the bag.

[0016] Finally, another drawback is that with this prior art machine, the mouth of the bag is not deformed or opened to facilitate introduction of a loading nozzle and opening of the valve for sealing thereof.

Technical Problem

[0017] In light of the prior art, the technical problem addressed by the present invention consists in providing a machine for automatically filling and sealing valve bags that affords a higher hourly throughput as compared with prior art plants.

Disclosure of the invention

[0018] The object of the present invention is to solve the aforementioned technical problem and obviate the above drawbacks, by providing a machine for automatically filling and selling valve bags that is highly efficient and relatively cost-effective.

[0019] A particular object of the present invention is to provide a machine as described hereinbefore that has a very high throughput.

[0020] Yet another object of the present invention is to provide a machine as described hereinbefore, that can limit material losses during the bag filling an closing processes.

[0021 ] A further object of the present invention is to provide a machine as described hereinbefore that can avoid damages to the bags during the bag filling and closing processes.

[0022] Another object of the present invention is to provide a machine as described hereinbefore that can reduce the time required to fill the bag.

[0023] A further object of the present invention is to provide a machine as described hereinbefore, that allows the bag valve to be exposed before sealing.

[0024] These and other objects, as more clearly explained hereafter, are fulfilled by a machine for filling and sealing valve bags with a filling mouth as defined in claim 1 , and comprising a load-bearing frame having filling means for filling one bag at a time, using a nozzle adapted to be introduced into each mouth, transfer means for picking up each bag from a pile or supply of empty bags and transfer it to the filling means along a first path, a sealing head of the ultrasonic type for sealing the valve of each bag, conveyor means for conveying filled and sealed bags toward a collection area and a computerized control unit for automatically controlling the filling means, the pick-up and transferring means, the sealing head, the support means and the conveyor means.

[0025] According to a peculiar aspect of the invention, the support means are adapted to move between the nozzle and the sealing head along a second path and the control unit is programmed to control the coordinated movement of the support means and the transfer means such that the displacement of each empty bag toward the nozzle and of each filled bag from the nozzle to the sealing head may be synchronized while preventing any interference of their respective paths and reducing the dead times of the two steps.

[0026] In a further aspect, the invention relates to a method of automatically filling and sealing valve bags using the above discussed machine as defined in claim 1 1 .

[0027] Advantageous embodiments of the invention are obtained in accordance with the dependent claims.

Brief description of the drawings

[0028] Further features and advantages of the invention will be more apparent from the detailed description of a preferred, non-exclusive embodiment of a machine for automatically filling and sealing valve bags with a filling mouth,, which is described as a non-limiting example with the help of the annexed drawings, in which:

FIGS. 1 and 2 are perspective front and rear views of the machine for filling and sealing bags of the invention respectively;

FIG. 3 is a side view of the machine of Fig. 1 ;

FIG. 4 is a top view of the machine of Fig. 1 ;

FIG. 5 is a perspective view of a bag adapted to be filled and closed using the machine of the present invention;

Fig. 6 is a perspective view of a first detail of the machine of Fig. 1 ; FIG. 7 is an enlarged perspective view of a second detail of the machine of Fig. 1 ;

Fig. 8 is a perspective view of a fourth detail of the machine of Fig. 1 ;

FIGS. 9 to 1 1 are perspective views of the machine of Fig. 1 in different operating positions;

FIG. 1 2 is a perspective view of the machine in a further operating position with a respective enlarged portion.

Detailed description of a preferred exemplary embodiment

[0029] Particularly referring to the above figures, there is shown a machine, generally designated by numeral 1 , for automatically filling and sealing valve bags B with at least one filling mouth M.

[0030] As best shown in FIG. 5, the bags B are generally made of paper and comprise a top portion P with the filling mouth M, having a predetermined length I, a closed bottom portion L and a pair of lateral sides S.

[0031] The filling mouth M is composed of a pair of facing edges C made of paper or other sheet-like materials, which slightly project out of the top portion P and may move toward and away from each other thereby generally defining a valve V. Each edge C has a respective adhesive strip in its inner side, which is adapted to be heated to adhere to the other strip and cause the mouth M to be sealed.

[0032] While a single type of bag is described and shown below, the bags may also comprise valves of different sizes and one or more filling mouths M.

[0033] The bags B may be filled with different solid materials, e.g. Of granular type, such as flours, feeds, seeds, fertilizers, yeasts or of inorganic type, such as powdered cement and plaster.

[0034] In the preferred embodiment of the invention, as shown in the figures, the machine 1 comprises a load-bearing frame 2 with filling means 3 mounted thereto for filling one bag B at a time, and comprising a nozzle 4 adapted to be introduced into the mouth M of each bag B and transfer means 5 for picking up the bags from one pile or supply 6 of empty bags and transferring it toward the filling means 3 along a second path T .

[0035] The supply 6 may contain a plurality of empty bags B stacked one on top of the other and may be mounted in a longitudinally offset position relative to the nozzle 4.

[0036] The filling material may be contained in a reservoir 7 situated inside the frame 2 and connected to the nozzle 4 and a plurality of weight sensors may be provided, which are adapted to allow delivery of a predetermined amount of solid material according to the size of the bag B in use.

[0037] The transfer means 5 may comprise a swinging arm 8 with a rigid portion 9 hinged to the frame 2 to pivot about a substantially horizontal axis H and a free end 10. Furthermore, the arm 8 may comprise a sliding stem 1 1 which extends from the rigid portion 9 and may be extended by an appropriate piston, not shown.

[0038] One or more suction cups 12 are fixed to the free end 10 of the arm 8, corresponding to the free end of the stem 1 1 , and are connected to a vacuum source for holding each bag B at its top portion P.

[0039] As the arm 8 pivots about the horizontal axis H and its longitudinal extent, the free end 10 that holds the top portion P of the bag B by means of the suction ups 1 2, may define the second path Ti in the air, for introducing the nozzle 4 into the mouth M of each bag B.

[0040] In a second embodiment of the machine 1 , not shown, the supply is placed in a longitudinally and transversely offset position relative to the filling means 3 and the arm 8 may be hinged to the load-bearing frame 2 to also pivot about a vertical axis V such that it may swing and transfer one bag at a time from the supply 6 to the nozzle 4.

[0041 ] Widening means 1 3 may be further provided, which are mounted to the swinging arm 8 to open out the mouth M of each bag B before fitting it onto the nozzle 4.

[0042] The widening means 1 3 may comprise the above described stem 1 1 and a pair of curved side members 14 attached to the rigid portion 9 of the arm 8.

[0043] The side members will be adapted to retain the lateral faces S of the bag B as the stem 1 1 slides upwards, the latter holding the top portion P of the bag B by the suction cups 1 2.

[0044] Thus, the bag B will be widened by opening the mouth M, which will assist opening thereof before fitting it onto the nozzle 4.

[0045] An ultrasonic sealing head 1 5 is mounted to the load-bearing frame

2, downstream from the filling means 3 for sealing the mouth M of each filled bag B proximate to the valve V and support means 1 6 of each bag B during filling and sealing.

[0046] As best shown in FIG. 6, the sealing head 1 5 may be mounted in a position distal to the filling means 3 and may comprise a transverse slit 1 7 and an ultrasound-emitting electrode facing the slit 1 7.

[0047] Possibly, each bag B may be retained at the support means 16 by at least one pair of pneumatic cylinders 1 9, rigidly joined to the frame 2.

[0048] The machine 1 has conveyor means 20 for conveying the filled and sealed bags B toward a collection area, which may preferably comprise a conveyor belt 21 located at the support means 1 6.

[0049] A computerized control unit is provided, not shown, which is connected to the filling means 3, the transfer means 5, the sealing head 15, the support means 16 and the conveyor means 20 for automatic and coordinated control thereof.

[0050] According to a peculiar aspect of the invention, the support means 1 6 are adapted to move between the nozzle 4 and the sealing head 1 5 along a first path T ₂ , as best shown in FIG. 4.

[0051 ] According to a peculiar aspect of the invention, the control unit is programmed to control the coordinated movement of the transfer means 5 and the support means 1 6 such that the displacement of each empty bag B toward the nozzle 4 and of each filled bag B from the nozzle 4 to the sealing head 1 5 may be synchronized while preventing any interference of their respective paths T-i , T ₂ and reducing the dead times of the two steps.

[0052] Therefore, the machine 1 allows a previously filled bag B to be sealed while a new empty bag B placed in the proximity of the filling means 3 is being filled, thereby affording a very high hourly throughput.

[0053] In the embodiment of the figures, the support means 1 6 comprise first 22 and second 23 carriages, moving on respective first 24 and second 25 slide guides 25, which extend in mutually perpendicular longitudinal X and transverse Y directions, as best shown in FIG. 4.

[0054] Particularly, the first carriage 21 comprises a platform 26 for supporting the bag B, located at the nozzle 4 and adapted to be moved in the respective longitudinal direction X by the filling means 3 toward the second carriage 23.

[0055] The platform 26 is slidably mounted to a vertical pillar 27 rigidly joined to the frame 2 such that its position may be adjusted in height according to the size of the bag B and is stably maintained at the nozzle 4.

[0056] The first carriage 22 also comprises a pair of side boards 28 joined by a transverse bracket 29 and capable of moving in the longitudinal direction X via the first slide guide 24. [0057] Once the second carriage 23 has received the filled bag B from the first carriage 22, it is moved in its respective transverse direction Y to carry the bag B toward the ultrasonic head 1 5, where the filling mouth M is sealed.

[0058] The combination of the two directions of displacement X, Y of the support means 1 6 defines the first path T ₂ for displacement of the filled bag B which is independent of the second path T for transfer of the empty bag B.

[0059] As shown in FIG. 9, the second carriage 23 is initially offset relative to the longitudinal direction X of displacement of the first carriage 22 so as not to impede transfer of the empty bag B to the filling means 3.

[0060] Later, once the bag B has been completely filled, the second carriage 23 is displaced in its transverse direction Y to be aligned with the longitudinal direction X of the first carriage 22 and the latter is moved to discharge the bag B onto the second carriage 23.

[0061 ] Furthermore, as soon as the first carriage 22, with its side boards 28 and its bracket 29, has discharged the bag B on the second carriage 23, it is immediately moved back to the nozzle 4 in the longitudinal direction X of the first guide 24 to receive a new back B picked up from the supply 6.

[0062] Advantageously, the second carriage 23 may also comprise respective pairs of substantially vertical side boards 28 for laterally retaining each bag B while it is being filled and transferred to the sealing head 1 5.

[0063] Therefore, unlike prior art arrangements, the present machine can fill, transfer and seal the bag B while constantly maintaining it in the vertical position.

[0064] This will avoid spillage of solid material during the processing steps as well as damage to the bag B as the latter is being overturned.

[0065] The second carriage 23 may have a depth p that is smaller than the length I of the top portion P of the bag B, so that the paper edges C with the filling mouth M may be exposed.

[0066] As the bag B is being transferred in the transverse direction Y, the filling mouth M with the valve V projecting out of the second carriage 23 is moved through the slit 1 7 of the ultrasonic head 1 5 to cause the adhesive to be heated and seal the mouth M by means of the electrode 1 8. [0067] Furthermore, the second carriage 23 comprises a tilt-out bottom 30, as shown in FIG. 1 2, which is acted upon by a pneumatic or electromechanical actuator, not shown, controlled by the computerized unit and adapted to be actuated after sealing the valve V to discharge the closed bag B onto the conveyor means 20.

[0068] The conveyor belt 21 extends along an axis that is substantially parallel to the transverse displacement direction Y to assist discharge of the closed bags B toward the collection area.

[0069] In a further aspect, the invention relates to a method of filling and sealing valve bags B with a filling mouth M using the above described machine 1 , whose operating steps are partially shown in FIGS. 1 and 9 to 1 2.

[0070] The method includes a step, as shown in FIG. 1 , of a) picking up and transferring a first bag B1 to be filled from the supply 6 of empty bags B toward the filling means 3 along a second path Ti and a step, as shown in FIG. 9, of b) filling the first bag B1 by the filling means 3.

[0071 ] Then a step is provided of c) transferring the first filled bag B1 from the filling means 3 to the sealing head 1 5 along the first path T ₂ , as partially shown in FIG. 10, followed by a step of d) sealing the filling mouth M of the bag B1 , as shown in FIG. 1 1 .

[0072] Finally, a step is provided of e) transferring the first sealed bag B1 to a collection area by the conveyor means 20, as shown in FIG. 1 2.

[0073] According to a further particular aspect of the invention, the method comprises an additional step, simultaneous to the step c), of f) picking up and transferring a second bag B2 to be filled, by the pick-up and transfer means 5 toward the filling means 3 along the second path T1 .

[0074] FIG. 1 1 shows the simultaneity of the two steps and that the second transfer path T of the second bag B2 does not interfere with the first transfer path T ₂ of the first bag B1 , as the bags are being filled and sealed.

[0075] The machine and method of the invention are susceptible to a number of changes or variants, within the inventive concept disclosed in the appended claims. All the details thereof may be replaced by other technically equivalent parts, and the materials may vary depending on different needs, without departure from the scope of the invention.

[0076] While the machine and the method have been described with particular reference to the accompanying figures, the numerals referred to in the disclosure and claims are only used for the sake of a better intelligibility of the invention and shall not be intended to limit the claimed scope in any manner.

Industrial Applicability

[0077] The present invention may find application in industry, because it can be produced on an industrial scale in factories operating in the field of packaging and bagging systems.